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Polycrystalline transparent In 2 O 3 semiconductive ceramics are successfully fabricated by oxygen atmosphere sintering for the first time. The starting rounded In 2 O 3 particles are obtained via pyrolyzing the nanoplate-like hydrated basic sulfate precursor prepared by a chemical precipitation route using hexamethylenetetramine as the precipitant. The silica additive dissolves into the In 2 O 3 lattice to form an interstitial solid solution, which promotes the diffusion rate during high-temperature densification process and thus helps to achieve good optical quality for In 2 O 3 ceramics. The created interstitial oxygen further compensates the oxygen vacancy in the ceramic body to result in a higher resistivity and lower carrier concentration / carrier mobility. The optical qualities of In 2 O 3 ceramics are also found to have slight effects on the resistivity, carrier mobility, carrier concentration, and Hall coefficient. Image, graphical abstract [ABSTRACT FROM AUTHOR]

High‐optical‐quality ternary [(Y1‐xGdx)0.99Dy0.01]2O3 (x = 0 and 0.4) ceramics were successfully fabricated by vacuum sintering with in‐line transmittances of 71.4%‐75.1% at 574 nm, the wavelength of Dy3+ emission (the 4F9/2 → 6H13/2 transition). Substitution of Gd3+ for Y3+ significantly affected the photoluminescent and scintillant properties of the ceramics. Gd3+ addition effectively increased lattice parameters and theoretical densities of the ceramic samples; this contributed to enhanced X‐ray absorption coefficients. Both [(Y1‐xGdx)0.99Dy0.01]2O3 (x = 0 and 0.4) ceramics displayed typical Dy3+ emissions from 4F9/2 → 6HJ (J = 15/2, 13/2, 11/2) transitions under UV and X‐ray irradiations. By incorporating Gd3+ into the lattice, a stronger excitation peak of Gd3+ due to internal f‐f transitions relative to Dy3+ was observed at 276 nm; subsequent ceramics obtained a sharper PL intensity and a warmer hue via effective energy transfer from Gd3+ to Dy3+. Using a Gd3+ dopant generally reduces the total photoluminescence/photoluminescence excitation intensities and light output; it also delays the lifetime and afterglow of the transparent ceramics. [ABSTRACT FROM AUTHOR]

In this work, chromium coating conducted by magnetron sputtering was introduced to braze SiC ceramics using inactive AgCu filler metal. The results showed that reliable metallurgical bonding of SiC ceramics was obtained at 900°C for 10 minutes. SEM, XRD, and TEM were used to identify the reaction phase in the joint, and the typical interfacial microstructure was SiC/mixed CrSi2 + Cr23C6 layer/CrSi2/Ag(s,s)+Cu(s,s)/CrSi2/mixed CrSi2 + Cr23C6 layer/SiC. The shear strength of SiC joint using chromium coating brazed with inactive AgCu filler metal was 29.6 MPa and the joint fractured at the SiC substrate entirely after shear test. The proposed active element coating method provides a feasible way to achieve the brazing of ceramics. [ABSTRACT FROM AUTHOR]